Table 1

Effects of ACh on α4β2 nAChRs expressed in Xenopusoocytes injected with cDNAs encoding α and β subunits in the ratios indicated

α4:β2 ratio	EC₅₀	n_H	E_max
	μM		%1 mm ACh
9:1	58.8 ± 14.7	1.33 ± 0.19	105.9 ± 2.7
1:1	65.6 ± 28.6^1-c	1.14 ± 0.07	106.1 ± 2.5
1:1^1-a	93.6 ± 14.7^1-c	1.36 ± 0.15	105.8 ± 1.7
1:9^1-b	1.84 ± 0.09^1-d	1.05 ± 0.05	89.3 ± 6.0

For each experimental condition, three concentration-effect curves, each obtained from a different oocyte, were fitted, and the values represent mean ± standard deviation of the estimated parameters.

↵1-a Reduced receptor expression level.
↵1-b Concentration-effect curve of the component more sensitive to ACh only.
↵1-c No statistical significant difference (t test; p = 0.21).
↵1-d Statistical significant difference (t test; p < 0.001) compared with all other groups.